Aspiration catheter having variable volume distal suction chamber

Abstract

An aspiration catheter is provided in which rapid withdrawal of a piston disposed within a distal region of a catheter lumen creates a sudden pressure drop for ingestion of intravascular matter into the catheter lumen through a distal port while avoiding large losses of suction common with catheters having long aspiration lumens. Conventional aspiration using the same catheter can subsequently complement the procedure by fully removing the ingested matter from the catheter.

1. A catheter for aspirating matter from within a blood vessel comprising:
 an elongate shaft with proximal and distal ends and having lumen terminating in a distal port at the distal end of the shaft; and 
 a sealing member slidably maintained within the distal region of the lumen and separating the lumen into proximal and distal segments, the distal segment of the lumen comprising a variable volume chamber disposed in communication with the distal port; 
 the sealing member being adapted to be rapidly withdrawn in the lumen from a first position to a second, more proximal, position to increase the volume of the distal chamber, thus creating a sudden reduction in pressure within the chamber for causing the matter to be aspirated into the variable volume chamber through the distal port. 
 
     
     
       2. The catheter as defined in  claim 1  wherein the sealing member is configured to be selectively transformable between an expanded profile configuration within the lumen, sealably slidable against an inner surface of the lumen, and a low profile configuration within the lumen having a reduced profile that enables flow from the distal segment of the lumen past the sealing member into the proximal segment of the lumen. 
     
     
       3. The catheter as defined in  claim 2  wherein the sealing member has an elongate rod extending proximally therefrom through the lumen and exiting the proximal end of the catheter to permit a clinician to selectively control the axial position of the sealing member within the lumen. 
     
     
       4. The catheter as defined in  claim 2  wherein the sealing member is transformable between its expanded and low profile configurations by a mechanical push-pull mechanism operatively connected to proximal and distal ends of the sealing member. 
     
     
       5. The catheter as defined in  claim 2  wherein the sealing member comprises an expandable and contractible tubular mesh having proximal and distal ends, the mesh having a low friction flexible outer impermeable layer adapted to seal against the inner surface of the lumen. 
     
     
       6. The catheter as defined in  claim 1  further comprising a source of negative pressure attached to the proximal segment of the lumen.